Improvement in piston-packing



PATENTED SEPT. 12, 1865.

w. BUCHANAN. PISTON PACKING.

V UNITED STATES PATENT Enrica.

\V ILLIAU BUCHANAN, OF NEV YORK, N. Y.

vlMPRCM/EMENT lN PlSTON PMCKlNG.

Specification forming part otl L etters Patent No. 49%53, dated September 12, 1 865.

To all whom it may concern:

Be it known that I, WILLIAM BUCHANAN, of the city and county of New York, and State of New Yorlghave invented a certain new and useful improvement in Pistons; and I do here by declare that the following is a full and exact description thereof.

The accompanying drawings form a part of this specification.

Figure 1 is a side elevation of the piston and packing. Fig. 2 is a cross-section on the line S S in Fig. 3. Fig. 3 is a longitudinal section on theliue T T in Fig. 2. Fig. i is a view of the tongue-piece l) detached.

Similar letters of reference indicate like parts in all the drawings.

To enable others skilled in the art to make and use my invention, I will proceed to do scribe its construction and operation by the aid of the drawings and of the letters of reference marked thereon.

A. is the body of the piston, and A the flange thereon. A is the follower, which is confined in the ordinary manner by bolts a.

B is a casting in the form of a ring, and which I term a bull-ring. it is fitted tightly by scraping or grinding to the inner faces of the flange A, and the follower A so that steam cannot pass. It is recessed or grooved on the exterior, as indicated. 1 have designated the central projection or ridge 1) and the ridges at the edges by b and b '0 and U are rings of rectangular section, which, with the aid of a tongue-piece adapted to each, described below, forms the packing proper. The width of each packing-ring G and O coincides with the width of the groove or space between the ridge 1) and b or b Each packing-ring is cut or divided at one point, as indicated, and it is narrowed near that point, and is also diminished in depth, as indicated. The depth or radial thickness of each of these packing-rings something less than the depth of the groove in which it is titted.

Each packing-ringis provided with a tongue.

piece, I), which prevents the passage of steam through the joint in the packing. The construction of this tongue and its application relatively to the adjacent surfaces of the packing are veryimportant. Aportioind,extendsacross the entire thickness of the packing,.a ads-owes to prevent the tonguepiece from slipping out i of place. The surface (l -is exactly parallel to the ridge 1), and the corresponding faces, 0, on the narrowed part of the packin g-rin g are also parallel to the said ridge. It follows that the packing-ring may expand and contract to a considerable extent by sliding the surfaces 0 against the surfaces d without opening any joint between these surfaces.

There is a part of each ton gue-piece D which extends across the whole width of the groove under each end of the packing, as represented. lts outer faces, (l are exactly concentric with the axis of the piston. The corresponding faces, 0*, on the inside of the thinned part of the packing, near the ends, are also concentric with the same axis. It follows that the packing-ring may extend and contract to a considerable extent by sliding these faces against the faces (l without opening any jointor escape for steam at those points. The depth of the entire tongue-piece is a ooiit equal to the full depth of the groove in which the packing lies. There is a groove, 15, on the under side of the tongne piece, as represented.

Holes M are formed in the piston on both faces, as represented. Corresponding holes, N, are formed in hnllring B, and are made to coincide in position exactly with the holes M, adowcl being fitted in the piston and in the bull-ring to prevent their changing their positions relatively to each other. The holes M and N allow the steam to enter from one face of the piston and fill the entire space under the packingring 0 and its tongue-piece D. The corresponding holes on the opposite side of the piston allow the steam to enter in a similar manner and till the space under the ring (Rand its tongue-piece D. The pressure of the steam on either face of the piston therefore serves to'hold the packing on that side, including the ring and the t0ngue-piece, out against the interior of the cylinder. When the prcssureot' the steam is relieved on that face these parts may yield inwardly. The admission of steam to the opposite face of the piston produces a corresponding outward pressure on the other set of packing. The steam cannot liow past either setof packing when thus forced outward by its pressure. As the packing wears, and the interior of the cylinder also wears, the pack i'i-g rings 0 and gradually expand themselves, and the tongue-pieces also gradually used it for a considerable period on a locoiner lZiVB using steam at a pressure of onev hundred pounds and upward and working at high vei locities. 1 made the bull-ring B of such dimen since as to apply in. an ordinary piston.

made .the packing-rings Q and (3 each half an inch wid'c on the face and halfan inch deep.

Imade the grooves -in which they fitted liveeighths of an inch deep, and made the steamtight faces 0" 02 about one and a half inch in length on each side of the dividing-web or thinned part (I. I madethe steam-tight surface 01* somewhat less in length and extended the tongue-piece under the entire body of the packing-ring, beyond thisthin portion of the packing-ring, as indicated in Fig.2. The packing-rings C C and their respective tongue- .pieccal) were allot ordinary oastdron. I found no difiiculty in introducing packingrings of this dimension in a piston of sixteen-inches-in inches in diameter by springing them in.

It will be evident that my packing will allow of various modifications in material and in dimensions. I propose 'to use this piston not only for locomotives and other steam-englues, but for air-pump sand other pumps and engines where pistons are required.

I do not consider the groove E absolutely essential tothe success of the other portions of myinvention. Itis important that the steam shall enter under the tongue-pieces D and force them outward with the same promptness as the packin g-rin gs to which they are fitted. In most instances the steam might do this without the grooves but the presence of these grooves renders itabsolntely certain that the steam canenter freely at each end of the tongue-pieces. The moment the steam has on;-

tered into this grooveit exerts a pressure out- Y ward, and immediately lifts the tongue-piece and allows the steam to enter under. the whole 3 of its under or inner surface. The side ridges,

b and b, when once fitted by grinding against the corresponding faces of the piston, require no further labor, There is no friction on those surfaces to induce wear, and the packingrings G .0 with their corresponding tongue-pieces, may be exchanged as often as is necessary without involving anygrinding.

Having now fully described my invention, what I claim as new therein, and desire to secure by Letters Patent, is as follows:

1. In combination with a pistonfA! A, the

single hull-ring 13, formed separate from the spider of the piston, and having the three ridges b h I)", with suitable packing in the spaces between the ridges, substantially as and for the purpose herein set fortlu v 2. A ton gue-piece, 1), adapted to defend the joint in thc-packing-ring 0 against the passage 'of steam both longitudinally and radially substantially in the manner and for the purpose herein set forth.

' -3. The surfaces d cl* on the tongue-piece 

